"Luckily, there were no serious injuries in this incident," said Marc Palmiter, supervisor with the Mercer County Department of Public Safety.

Still, at least 17 motorists were taken to area hospitals from a triage area set up at a Quality Inn in Hermitage, Pennsylvania, two miles from the pileup site, said Dr. Sergio Segarra, medical director of the command facility and a specialist in emergency medicine.

Others with more severe injuries were taken directly to hospitals from the crash site, he said.

The accident occurred in the westbound lanes of the coast-to-coast highway shortly before 11:30 a.m., but traffic was halted in both directions, Segarra said.

The county went on a mass-casualty alert as soon as the crash was reported, with doctors reporting for duty at the hotel, he said.

Eleven patients were sent to Sharon Regional Health System in Sharon, Pennsylvania, and six to Pittsburgh Medical Center in Farrell, some suffering chest pain, others bruises, Segarra said.

No one had been charged by Sunday night, but Silloway said excessive speed was probably to blame.

"Everybody thinks they're invincible, I guess," he said.

"It looked like a battle zone, it really did," said CNN producer Paul Ferguson, who was driving with his brother Bernard in a van about a quarter-mile behind the accident when the pileup began.

Ferguson said he and his brother -- an emergency room physician in New London, Connecticut -- looked for injured people at the scene after walking to the site of the wrecks.

Ferguson said they arrived before the ambulances did, finding four 18-wheelers jackknifed across the road. Dozens of cars had smashed into them and were littered about the crash site, some on their sides.

"It was a vision of hell," Paul Ferguson said.

Melody Glaser, acting general manager of the Quality Inn, spoke to CNN on the phone Sunday afternoon.

"They asked if they could set up our hotel as emergency central and we told them, 'Of course,'" Glaser said shortly after a bus with 19 motorists arrived from the accident site. The injured were given medical help, blankets and towels.

Guests of the hotel, which was about 50 percent occupied, moved their cars to clear the parking lot for emergency vehicles, she said.

"I probably have 20 ambulances here and about five or six fire trucks and rescue vehicles."

Heavy snow continued to fall during the afternoon, and Glaser said her typical 4-minute drive to work Sunday morning on smaller roads had taken her more than an hour.